The semiconductor Integrated Circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
Integrated circuits are typically formed onto a semiconductor wafer. Various photolithographic processes are used to form the individual components that make up the integrated circuit into the wafer. Such components include transistors, capacitors, and metal contacts. One type of photolithographic process used to form such components is an Extreme Ultra-Violet (EUV) lithographic process. An EUV lithographic process involves projecting electromagnetic radiation having a wavelength between 10 nanometers (nm) and 120 nm onto the wafer. At such a small wavelength, the electromagnetic radiation is absorbed by air and thus the process has to be performed in a vacuum to avoid such absorption.
When performing an EUV lithography process, a chuck is used to secure a wafer within a vacuum chamber for the duration of the process. One example of a type of chuck is an Electronic chuck (E-chuck). An E-chuck includes a charged plate that uses static electrical forces to secure the semiconductor wafer to the chuck. For example, a particular portion of the wafer may be positively charged. The corresponding plate on the E-chuck is then negatively charged. These opposite charges provide an attractive force that securely holds the wafer in place during the EUV process. In some cases, the stress from the static electrical force on the wafer may cause irregularities within the wafer. To relieve the force placed on the wafer, a gas is pumped through the E-chuck to the backside of the wafer. This gas is pressurized to provide an opposing force to the static electrical force. The opposing force is designed to be strong enough to relieve the pressure on the wafer while still allowing the wafer to be secured in place for the EUV lithographic process.